# Tag Info

16

Planets and stars, no. Globular clusters and galaxies, yes. Small scales To condense into such relatively compact objects as planets, stars, and even the more diffuse star-forming clouds, particles need to be able to dissipate their energy. If they don't do this, their velocities prohibit them from forming anything. "Normal" particles, i.e. atoms, do this ...

11

Surface gravitational acceleration on an object with mass $M$ and radius $R$ is given by $$g = \frac{GM}{R^2} \propto G\rho R$$ where $\rho \propto M/R^3$ is the density of the object. Titan is larger than Earth's Moon, so it must be less dense. Wikipedia confirms: $R_\text{Titan} = 1.5 R_\text{Moon}$, but $\rho_\text{Moon} = 3.34\rm\,g/cm^3$ while ...

3

In some models of quantum gravity there are 10 dimensions. 7 of these are curled up and very small. Gravity is a force it is not a dimension. If these models of quantum gravity is correct then we do live in these 10 dimension. If these models are correct then we do live in "hyperspace", but only 3 dimensions are macroscopic. Dimensions don't govern the ...

2

If you mean the escape velocity of the Earth, then no. Any meteor that enters the earth's atmosphere and burns up or collides with the earth must have had higher than the escape velocity, purely because they were not from that one body. Unless of course as you say they have ricocheted of another object in orbit sufficiently reducing the kinetic energy to ...

1

The comments from @userLTK, and @Lacklub are correct. Lets assume there is an object of radius $R$ and mass $M$, from a Newtonian point of view, if you are at another radius $r$, such that $r > R$, then there is no difference in the gravitational field experience by an object at $r$ if the mass spread across a shell of radius $R$ or if its concentrated ...

1

Upon some google-ing and wiki-ing I found this image of a gravity map of the moon: That scale up the top is measured in milli-Gal which is thousandths of a cm/s^2. For scale gravity is ~9.81m/s^2 which equals ~981000mGal. The difference between gravity at sea level and the top of mount everest is 2Gal, or 2000mGal, which is 0.2% of average gravity. On the ...

Only top voted, non community-wiki answers of a minimum length are eligible